This section provides background information related to the present disclosure which is not necessarily prior art.
Commercial food waste disposers such as those used in restaurants typically have a source of flushing water provided to them, either directly or to the sink to which the food waste disposer is attached. Various systems for controlling the flow of this flushing water are known. One such system is described in U.S. Pat. No. 5,308,000, a portion of which follows.
With reference to FIG. 1 of U.S. Pat. No. 5,308,000, a commercial food waste disposer 10 of conventional design is shown. Disposer 10 is connected in conventional fashion to a drain opening 14 of a sink 12. An outlet 16 is connected to a sanitary sewer system. Disposer 10 includes an upper grind chamber 13 and an electric motor 18 that powers a grind mechanism (not shown) in the grind chamber. Conduit 28 which includes parallel branches 27 and 29 and valves 36, 40 is connected to a source of flushing water that is discharged into grind chamber 13.
Referring to FIG. 2 of U.S. Pat. No. 5,308,000, motor 18 is connected to an AC power source 22. The flow of electrical current through motor windings 20 is controlled by a switch 23. Electrical lead wires 24 and 26 are, thus, energized when switch 23 is closed. A schematically illustrated current sensor 30 is provided to sense the flow of current through winding 20 and hence through lead 24. In the illustrated embodiment, a toroid 32 is shown as an example of an induction operated device that responds to the flow of current through lead 24 and causes a switch 33 to be closed whenever a grind load is placed in disposer 10. It will be further noted in FIG. 2 that when switch 23 is closed, a first solenoid 34 is energized and causes opening of a valve 36 allowing water to flow at a low rate through conduit 27 and into grind chamber 13. It will be apparent that solenoid 34 is, thus, activated whenever there is power provided to motor winding 20. Valve 36 is preferably designed so that approximately one to two gallons per minute of water will flow through conduit 27.
When a grind load is encountered by the passage of material from sink 12 into disposer 10, the increased current flow through winding 20 is sensed by current sensor 30. Current sensor 30 causes a second solenoid 38 to open valve 40 allowing water to flow through conduit 29. Valve 40 and conduit 29 are configured so that water will flow at a relatively higher rate, preferably in the range of about 3 to 7 gallons per minute. When the grind load has discontinued the flow of current through winding 20 diminishes to the point that switch 33 is once again opened due to a drop in the current induced in toroid 32. This causes valve 40 to once again be closed thereby conserving water when no grind load is sensed. A time delay can be designed into the circuitry so that valve 40 will not be closed until there has been no grind load detected for a selected period of time, for example 10 seconds. This will help ensure the thorough flushing of ground materials out of outlet 16.
In the further embodiment of FIG. 3 of U.S. Pat. No. 5,308,000, a current detector 48 is connected to a variable solenoid 50 that will progressively increase the opening of a valve 52 in response to the amount of current flowing through motor windings 20. With this arrangement, sensor 48 can be utilized to trigger a low rate of flow in the one to two gallon range through conduit 28 when switch 23 is closed. As increased amounts of current flow through winding 20, variable solenoid 50 can be set to allow progressively increasing amounts of water to flow through conduit 28 into the grind chamber 13.
Current sensors 30 and 48 can be of various types. Preferably an induction operated device is used such as a current transformer, watt meter, or if desired, an ammeter. A preferred type of sensor is marketed by Solid State Advance Controls, Inc. as an “alternating current sensor” and is provided with adjustable sensitivity. As previously noted, a number of solenoids greater than two can be utilized. Thus, for example, if low, medium and high rates of water flow are desired, three solenoids are used instead of two.
It should be understood that types of valves other than solenoid valves can be used, such as pneumatically or hydraulically controlled valves.
While the above described system advantageously conserves water by controlling the flow of flushing water to disposer 10, it uses motor current as the basis for controlling the water supply. In some instances, such as where the grind load is light, the load placed on the motor when the food waste is being ground may not be large enough to cause a sufficient change in motor current so as to trigger the detection system.